Improvement in left ventricular wall motion following nitroglycerin

A Pilot Evaluation Study of Diffuse Coronary Arterial Contraction Causing Ischemia by Double Measurement of Left Ventriculography Before and After Intracoronary Administration of Nitrates

Background: Abnormal diffuse coronary artery contraction is not easily diagnosed. In order to evaluate its true risk, we performed double left ventriculography (LVG) before and after intracoronary administration of isosorbide dinitrate (ISDN). We also investigated the relationship between changes in coronary lumen area and changes in left ventricular ejection fraction (LVEF) after ISDN.

Methods and Results: The study included 53 patients who underwent an acetylcholine (ACh) provocation test after coronary angiogram and LVG. The second LVG was performed after intracoronary ISDN administration. Coronary lumen area was measured by quantitative coronary arteriography (QCA). Simple and multiple regression analyses showed a significant correlation between changes in total QCA area before and after ISDN administration (pre-and post-total QCA area, respectively) and changes in LVEF. Using structural equation modeling, we observed a negative effect of pre-total QCA area and a positive effect of post-total QCA area on LVEF improvement. Importantly, LVEF improvement was similar between the ACh-positive and -negative groups on the coronary artery spasm test. Receiver operating characteristic curves indicated that the cut-off value at which changes in total QCA area affected changes in LVEF was 5%.

Conclusions: Performing double LVG tests before and after ISDN administration may detect myocardial ischemia caused by diffuse coronary artery contraction. The addition of this method to the conventional ACh provocation test may detect the presence of local and/or global myocardial ischemia.

Efficacy of different forms of nitrates in angina pectoris

Nitroglycerin has maintained its position in the treatment of angina pectoris for more than a century. Efficacy of oral nitrates has been established and compares well with that of other anti-anginal drugs. New delivery systems are being developed for sustained systemic nitrate action. Beneficial action of nitrates in congestive heart failure and their crucial role in unstable angina and acute myocardial infarction has further widened their therapeutic use. A plausible hypothesis of the mechanism of nitrate-induced vasodilation has been presented, involving production of nitrosothiols and activation of guanylate cyclase in the vascular smooth muscle. Recent developments suggest that the rate degradation of nitrates and formation of nitrosothiols in the vascular smooth muscle are linked, offering an explanation to the relatively rapidly developing, but partial vascular tolerance during high-dose nitrate therapy.

Exercise-induced ST-elevation is related to left ventricular dysfunction but not to myocardial viability in patients with healed myocardial infarction

BACKGROUND

Exercise-induced ST-segment elevation was proposed as a marker of myocardial viability after a recent myocardial infarction.

AIMS

The aim of this study was to evaluate whether exercise-induced ST segment elevation is related to viability or to left ventricular dysfunction in patients with history of old Q wave myocardial infarction.

METHODS

Fifty patients (43 men, age 57+/-11 years) were studied 31+/-49 months after a Q wave myocardial infarction. They all underwent stress, reinjection-redistribution, and late redistribution Tl-201 SPECT, completed by equilibrium radionuclide angiography. Viability was defined by defect reversibility or significant (>60%) persistent Tl-201 uptake in dyssinergic segments on late redistribution SPECT. Relative post-exercise and reinjection-redistribution LV volumes were calculated using validated software (QGS).

RESULTS

Twenty-one out of 50 patients (42%, G1) had significant stress-induced ST-elevation (>1 mm 80 ms after J point in at least 2 ECG leads with Q wave), and 29/50 (58%, G2) did not. Seventeen out of 50 patients (34%) demonstrated myocardial viability on late redistribution scan. The diagnostic accuracy of exercise-induced ST-elevation was only 52% for viability assessment. Significant LVEF reduction and increased relative LV volumes were observed in G1 compared to G2 (LVEF: 39+/-10% vs. 49+/-11%, P=0.003; post-stress LV volume: 134+/-98 ml vs. 81+/-41 ml, P<0.02; reinjection-redistribution LV volume: 123+/-86 ml vs. 79+/-40 ml; P<0.02). Perfusion defects were similar in G1 and G2 (post-exercise: 38+/-12% vs. 37+/-14%, ns; reinjection-redistribution: 31+/-11% vs. 30+/-11%, ns; late redistribution: 30+/-10% vs. 28+/-11%, ns).

CONCLUSION

These results suggest that, in patients with history of myocardial infarction, exercise-induced ST-segment elevation is not related to persistent myocardial viability but is associated to left ventricular dysfunction.

Assessment of viable myocardium and prediction of postoperative improvement in left ventricular function in patients with severe left ventricular dysfunction by quantitative planar stress-redistribution-reinjection 201-T1 imaging

A noninvasive approach to determine viable but asynergic myocardium will be clinically significant in identifying patients with coronary artery disease and severe left ventricular dysfunction who will benefit most from coronary bypass surgery. Accordingly, 12 patients (mean ejection fraction 0.32 +/- 0.03) underwent quantitative planar stress-redistribution-reinjection thallium scintigraphy and radionuclide ventriculography before and 8 weeks after revascularization for viability and segmental and global left ventricular function assessment, respectively. Reinjection scan showed new fill-in in 63% of segments without redistribution. Postoperative improvement in perfusion and function of asynergic segments were significantly better in viable compared to nonviable segments (P < 0.001, P < 0.01, respectively) with a strong correlation between improvement in 201-T1 uptake and function (P < 0.001). When adequacy of revascularization was considered, the predictive value of a positive preoperative viability test for functional improvement was 83%. Finally, mean ejection fraction and global wall motion score increased significantly after revascularization for the group as a whole (0.32 +/- 0.03 to 0.44 +/- 0.04, P < 0.001 and 24.08 +/- 2.90 to 33.16 +/- 3.32, P < 0.001, respectively). Thus, preoperative quantitative planar stress-redistribution-reinjection thallium imaging detects viable but asynergic segments which improve function postoperatively and may be valuable in selection of patients with severe left ventricular dysfunction for revascularization.

Identification of viable myocardium by nitrate echocardiography after myocardial infarction: comparison with planar thallium reinjection scintigraphy

BACKGROUND

The aim of this study was to validate a new diagnostic tool, nitrate echocardiography (NE), for the identification of viable noncontracting myocardium in patients with a history of prior myocardial infarction (MI). Nitroglycerin (NTG) may be useful for this purpose for its peculiar pharmacodynamic action and may represent an option other than dobutamine echocardiography for the detection of hibernating segments in the presence of severely reduced coronary reserve.

METHODS

Twenty selected patients (pts) with an old MI were studied with NE and planar thallium scintigraphy with reinjection. NE was performed by administering i.v. NTG starting at 0.4 mcg/kg/minute with equal increments every five minutes up to 2 mcg/kg/minute or to early interruption of the test (decrease of systolic blood pressure > or = 20% or improvement of previously akinetic segments). Left ventricular wall motion was analyzed by dividing the left ventricle (LV) into 16 segments, and a wall motion score index (WMSI) was calculated. Thallium images were obtained at peak exercise, at four hours, and after reinjection. Myocardial viability was defined as an improvement in thallium uptake after reinjection in fixed defects.

RESULTS

Basal echo demonstrated 74 akinetic segments; of these 21 (28%, 11 pts) showed improved contractility during NTG infusion at a mean dose of 0.87 +/-0.33 mcg/kg/minute. WMSI decreased from 1.69 +/- 0.29 to 1.46 +/- 0.31 (P = .001). The only hemodynamic response was a drop in systolic blood pressure (136 mmHg to 124; P = .02). Thallium studies showed 29 segments with a four-hour reversible defect and 79 segments with a four-hour fixed defect; of the latter, 14 regions demonstrated improvement in tracer uptake after reinjection (17.7%; 10 pts). Nine pts had a positive echo and thallium study, while 8 showed no improvement either during NE or after thallium reinjection. Two pts had a false-positive nitrate echocardiogram. Therefore, according to an echo/thallium study match, sensitivity, specificity, and accuracy are 90%, 80%, 85%, respectively.

CONCLUSION

NE is a reliable and low-cost method for the detection of viable noncontracting myocardium in selected patients with CAD but needs further validation for widespread application.

Specificity and sensitivity of exercise-induced ST segment elevation for detection of residual viability: comparison with fluorodeoxyglucose and positron emission tomography

OBJECTIVES

We evaluated the sensitivity and specificity of exercise-induced ST segment elevation for the detection of residual myocardial viability.

BACKGROUND

Assessment of residual viability after myocardial infarction is relevant for establishing indication for revascularization. We have previously shown that exercise-induced ST segment elevation is a marker of residual viability.

METHODS

We studied 34 patients with a previous Q wave myocardial infarction (anterior in 21, inferior in 13) of whom 18 (group A) had exercise-induced ST segment elevation in more than one lead (mean [+/- SD] 1.8 +/- 0.9 mm, range 1 to 4) and 16 (group B) did not. All patients underwent rest technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography (SPECT), fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography and coronary angiography. The time elapsed between the infarction and the viability study was 72 +/- 108 days (range 15 to 400) in group A and 516 +/- 545 days (range 14 to 1,800) in group B.

RESULTS

The presence and site of previous infarction were confirmed by SPECT studies in all 34 patients. Uptake of F-18 fluorodeoxyglucose within the infarcted area was present in 18 of 18 patients in group A but in only 9 (56%) of 16 in group B (p < 0.01). In patients with an anterior infarction, the sensitivity, specificity and predictive accuracy of exercise-induced ST segment elevation for detection of residual viability were 82%, 100% and 86%, respectively (95% confidence intervals 46% to 83.5%, 59% to 100% and 55.6% to 87.1%, respectively).

CONCLUSIONS

Exercise-induced ST segment elevation in infarct-related leads has a high specificity and acceptable sensitivity for detection of residual viability within the infarcted area.

Assessment of residual tissue viability by exercise testing in recent myocardial infarction: comparison of the electrocardiogram and myocardial perfusion scintigraphy

The assessment of residual myocardial viability in infarcted areas is relevant for subsequent management and prognosis but requires expensive technology. To evaluate the possibility that simple, easily obtainable clinical markers may detect the presence of within-infarct viable tissue, the significance of exercise-induced ST elevation occurring in leads exploring the area of a recent Q wave myocardial infarction was assessed. Twenty-five patients with recent (less than 6 months) myocardial infarction were studied. All had angiographically documented coronary artery disease, diagnostic Q waves (n = 24) or negative T waves (n = 25) on the rest 12-lead electrocardiogram and exhibited during exercise greater than or equal to 1.5 mm ST segment elevation (n = 17) or isolated T wave pseudonormalization (n = 8) in the infarct-related leads. ST-T wave changes were reproduced in all patients during thallium-201 exercise myocardial scintigraphy. A fixed perfusion defect was observed in 24 of the 25 patients. A reversible defect was seen in 16 (94%) of 17 patients who exhibited transient ST elevation during exercise but in only 4 (50%) of the 8 patients who had only T wave pseudonormalization. In conclusion, in patients with recent myocardial infarction, analysis of simple ST segment variables obtained during exercise testing may allow a first-line discrimination of those who may potentially benefit from a revascularization procedure.

Dipyridamole perfusion scintigraphy

Dipyridamole is one of several agents that may be infused intravenously to nonivasively evaluate coronary perfusion without dynamic exercise. Among such agents it is the most investigated, and it is associated with the greatest clinical experience. Its mechanism of action utilizes intrinsic adenosine and does not require the induction of ischemia. Rather, the method tests the coronary flow reserve by dilating the precapillary and arteriolar capillary beds. Vessels with a limited coronary flow reserve demonstrate reduced responsiveness with relative flow reduction and a resultant defect on perfusion scintigraphy. Side effects are common and generally benign, but deaths have been reported and they generally relate to severe hypotension, prolonged dense ischemia and resultant infarction, or bronchospasm. Severe complications are rare and can be avoided by the prompt administration of aminophylline, the dipyridample antedote. Diagnostic accuracy for the identification of coronary disease appears similar to that for exercise perfusion scintigraphy. It should be applied to patients with known or suspected coronary disease who require coronary evaluation, but who cannot exercise adequately for diagnostic or prognostic purposes. In such patients, the method is useful for the preoperative assessment of risk at peripheral vascular and other major noncardiac surgery. It may be of value as well in the assessment of the otherwise uncomplicated patient postinfarction. Not yet established is its application to the patient with unstable angina or in the acute setting, after coronary reperfusion. Similarly, its comparison with direct adenosine infusion or with pharmacological agents whose mechanism rests entirely on ischemia induction, as does dobutamine, has until now been limited. Unlike its use with perfusion scintigraphy, the application of dipyridamole with echocardiography and other functional ischemic indicators is totally dependent on the induction of ischemia. This is likely less frequent than the induction of nonischemic perfusion heterogeneity. The agent is now commonly available and will make a significant beneficial impact on patient evaluation and management.

Significance of collateral circulation in reversible left ventricular asynergy by nitroglycerin in patients with relatively recent myocardial infarction

To evaluate the functional role of coronary collateral circulation in reversible asynergy of the left ventricle, cineventriculography was performed before and after the administration of sublingual nitroglycerin in 19 patients with complete occlusion of the proximal part of the left anterior descending coronary artery. In nine patients who had significant collateral circulation to the infarct-related coronary artery (group A), there was significant improvement in both the left ventricular ejection fraction (53% to 60%, p less than 0.05) and regional wall motion in the infarct zone (8% to 18%, p less than 0.01 in the anterolateral area) with administration of nitroglycerin. In contrast, in the remaining 10 patients without significant collateral perfusion (group B), there were no detectable changes in either global function (49% versus 50%) or regional wall motion (6% versus 8% in the anterolateral area) before and after nitroglycerin. Changes in heart rate and left ventricular peak systolic and end-diastolic pressures with nitroglycerin were comparable in both groups. These results suggest that angiographically demonstrable collaterals preserve viable myocardium, which can improve its contraction when the supply-demand relationship is favorably affected because of increased collateral flow and/or more favorable loading conditions produced by nitroglycerin.

Pharmacodynamic monitoring during acute intervention in ischaemic heart disease using a new echo-Doppler device

1. We have utilised a new non-imaging echo-Doppler cardiac output device, using the principle of attenuated compensated volume flow (ACVF), to assess the cardiovascular effects of atenolol and buccal nitroglycerin (NTG) in a placebo-controlled study of 30 patients with coronary disease. 2. Atenolol (4 mg i.v.) reduced heart rate, cardiac output and time-averaged mean aortic velocity (P less than 0.01) and increased systemic vascular resistance (P less than 0.01). 3. Buccal NTG (5 mg) reduced systemic mean arterial pressure (P less than 0.01), cardiac stroke volume (P less than 0.05) and stroke length (P less than 0.01). 4. Thus although both drugs reduced time-averaged aortic velocity (an index of cardiac performance), the concomitant reduction in cardiac stroke length and tachycardia suggested sub-optimal cardiac filling for buccal NTG, whereas for atenolol (with the associated increased systemic vascular resistance but unchanged stroke length) attenuation of sympathetic stimulation at cardiac beta-adrenoceptors. 5. The ACVF method of cardiovascular monitoring should prove useful in human pharmacodynamic studies.

Effects of nicorandil on left ventricular hemodynamics and volume at rest and during exercise-induced angina pectoris

The hemodynamic effects of nicorandil (20 mg) were compared with placebo in a double-blind study of 20 patients with angiographically proved coronary artery disease at rest before and 7, 15, 30 and 60 minutes after oral dosing. The impact of the drug on left ventricular (LV) hemodynamics and volume during exercise-induced angina was determined by repeating exercise 60 minutes after drug administration, at the same work load that reliably induced angina during control predrug exercise. At rest, nicorandil reduced all components of systemic arterial pressure without change in cardiac or stroke volume indexes or heart rate. Pulmonary artery occluded pressure was reduced without change in LV ejection fraction or systemic vascular resistance index. Effects were evident at 7 minutes and peaked at 30 minutes with attenuation at 60 minutes. Compared with control supine bicycle exercise, the drug (at 60 minutes) reduced mean systemic arterial pressure and LV filling pressure without change in cardiac stroke volume indexes and heart rate. There was a smaller increase in LV ejection fraction. These data suggested greatest impact on LV function during exercise when substantial decreases in filling pressure occurred at maintained cardiac pumping indexes.

The hibernating myocardium

The hibernating myocardium refers to resting LV dysfunction due to reduced coronary blood flow that can be partially or completely reversed by myocardial revascularization and/or by reducing myocardial oxygen demand. It is different from the stunned myocardium. Methods for its detection are not yet perfect. Hibernating myocardium has been demonstrated to be present in several clinical subgroups of patients; however, currently its full clinical presence and impact are not adequately defined.

A rest and exercise haemodynamic evaluation of a new cardio-selective beta-adrenoceptor blocker celiprolol alone and in combination with nitroglycerine in ischaemic heart disease

The symptomatic benefits of combining beta-adrenoceptor blockers and nitrates in angina pectoris are well recognised. Their actions on cardiac haemodynamics and volumes when combined have been poorly characterized. Accordingly this study investigated a new cardioselective beta-adrenoceptor blocking agent celiprolol and buccal nitroglycerine in 24 patients with angiographically documented coronary artery disease. Following a control period, with confirmed stable haemodynamics, three groups (n = 8/group) of prospectively matched patients, were studied following intravenous celiprolol (8 mg), buccal nitrate (10 mg) or their combination. Haemodynamics and left ventricular ejection fraction (nuclear probe) were determined following each intervention. The actions of each regimen on the haemodynamics of exercise-induced angina were compared by exercise testing in the control state and following each regimen. At rest, celiprolol did not alter haemodynamic parameters. Nitrate therapy reduced left ventricular filling pressure (pulmonary artery occluded pressure--PAOP) and volumes; the ejection fraction and heart rate increased. Combination therapy resulted in a highly significant reduction in left ventricular preload and afterload (PAOP and mean arterial blood pressure) at an increased left ventricular ejection fraction and reduced cardiac volumes; there was a trend to reduce cardiac double product (HR X SBP). During exercise celiprolol reduced systolic blood pressure, heart rate and cardiac index; systemic vascular resistance index increased. Nitrate therapy reduced blood pressure and PAOP, and increased ejection fraction. Combination therapy reduced all components of the triple product (heart rate, systolic blood pressure and PAOP) without affecting the other haemodynamic or radionuclide parameters. These data suggest improvements in cardiac function from the combination of celiprolol and nitrate therapy which were not achieved by either agent when used as monotherapy; they afford an interesting insight into the manner in which such widely utilised therapeutic modalities interact in coronary artery disease.

The influence of anatomic evolution of coronary artery disease on left ventricular contraction: an angiographic follow-up study of 300 nonoperated patients

The impact of the evolution of obstructive coronary artery disease (CAD) on left ventricular (LV) function was studied in 300 nonoperated patients who had had two angiographic studies. The interval between studies ranged from 6 months to 10 years (mean 29.6 months). Quantitative analysis of LV contractions in right anterior oblique projections was performed with the use of a computer program for calculation of ejection fraction (EF) and regional wall motion (RWM) according to the method of Leighton. No progression of CAD was found in 131 patients. Progression of CAD was found in 169 patients. In the patients without progression and in 75 patients who had progression to less than total obstruction, no changes in EF and RWM were found. In the 67 patients in whom progression from less than 90% narrowing to occlusion had occurred a significant decrease in EF and RWM was found. In the 27 patients with progression from subtotal narrowing to occlusion, however, no change in LV function was found. A myocardial protective value of angiographically visible preexistent collaterals could not be demonstrated. We conclude that absence of progression of CAD implies that LV function does not deteriorate and that slow progression to occlusion, via a stage of subtotal narrowing, generally does not influence LV function.

Left ventricular dyskinesia reversed by intravenous nitroglycerin: a manifestation of silent myocardial ischemia

Patients with coronary artery disease (CAD) frequently have left ventricular (LV) wall motion abnormalities in the absence of symptoms. Thirty-one patients with such LV wall motion abnormalities in the absence of symptoms participated in a study of the response of these abnormalities to ascending doses of intravenous nitroglycerin (NTG). In a subgroup of 20 patients the relation between the location of LV wall motion abnormalities and the presence or absence of significant CAD (greater than or equal to 50% diameter reduction), in the vessel supplying the LV region, was assessed. Wall motion improved after intravenous NTG; the ejection fraction increased by 3.7% (mean p less than 0.05) and by 9.4% in the 19 patients who responded. There was no significant increase in heart rate; both LV systolic and end-diastolic pressures decreased minimally (12.5 and 3.5 mm Hg, respectively, p less than 0.05). The ejection fraction response was observed with NTG doses less than or equal to 200 micrograms and no dose-response relation was apparent. In the subgroup subjected to regional wall motion analysis, the presence of dyskinesia was significantly (p = 0.007) associated with the presence of important CAD in a vessel supplying that region. Further, the fact that wall motion improvement after NTG was significantly (p = 0.002) associated supports the concept that silent ischemia results in LV regional wall motion abnormalities, which can be reversed with low dose intravenous NTG.

Electrocardiographic diagnosis of posterior myocardial infarction revisited: a new approach using a multivariate discriminant analysis and thallium-201 myocardial scintigraphy

This study examined the feasibility of using a multivariate discriminant analysis to design a useful electrocardiographic (ECG) model to diagnose posterior myocardial infarction (MI). Thallium-20) scintigraphy was used as a reference standard to identify posterior scar (fixed perfusion defects). The model was derived from 111 patients of whom 37 had fixed posterior defects and 74 had normal images, and its validity was subsequently tested in a separate group of 180 patients. In the initial group of patients, the fixed perfusion defects involved the posterior left ventricular wall alone in 15 patients, and the posterior and inferior walls in 22 patients. Stepwise multivariate discriminant analysis of 26 ECG variables produced a model of two variables (Q-wave duration in a VF and T-wave amplitude in V1) which provided a sensitivity of 78%, a specificity of 89%, and a predictive accuracy of 86% for the diagnosis of posterior MI. This model, when tested in the second group of 180 patients, yielded an overall prediction accuracy of 82% (sensitivity 65%, specificity 85%). Thus, the combination of Q-wave in a VF and upright T wave in V1 is the best ECG predictor of posterior MI. These two variables reflect the frequent association of posterior MI with inferior MI, and the reciprocal repolarization changes in the right precordial leads.

Effects of buccal nitrate on left ventricular haemodynamics and volume at rest and during exercise-induced angina

A novel approach has been employed to characterize the effects of a cardioactive drug on left ventricular haemodynamics and volume by simultaneously determining cardiac stroke volume (thermodilution) and left ventricular ejection fraction (nuclear probe). The effects of glyceryl trinitrate were evaluated in 12 patients with angiographically proven coronary artery disease at rest and 3, 7, 15 and 30 min following 10 mg buccal nitroglycerin (Suscard) administration. The impact of the drug on left ventricular haemodynamics and volume during exercise-induced angina was determined by repeating exercise 30 min following drug administration, at the workload that reliably induced angina during control exercise. At rest buccal nitroglycerin reduced systemic arterial pressure, cardiac and stroke volume indices, and increased heart rate. The left ventricular ejection fraction (E.F.) increased; its filling pressure together with end-diastolic and end-systolic volumes were significantly reduced. Compared with control supine-bicycle exercise, the drug reduced mean systemic arterial pressure and left ventricular filling pressure without change in cardiac and stroke volume indices. There was a smaller increase in left ventricular volume during exercise, and the fall in E.F. was attenuated. These data demonstrated differential actions of glyceryl trinitrate on left ventricular function related to the physiological state in obstructive coronary artery disease. These techniques appear to hold promise in the evaluation of the effects of other therapies on left ventricular volume in coronary artery disease.

Improvement in regional wall motion and left ventricular relaxation after administration of diltiazem in patients with coronary artery disease

To assess the effect of diltiazem on left ventricular systolic regional wall motion and diastolic function in patients with coronary artery disease (CAD), 22 patients underwent biplane left ventricular cineangiography before and after intravenous diltiazem (plasma concentration 154 +/- 12 ng/ml). Left ventricular and right ventricular pressures were measured by micromanometer-tipped catheters. Regional wall motion was assessed quantitatively with an area ejection fraction technique. Diltiazem decreased mean arterial pressure 11.5% (p less than .0001) and heart rate 6.8% (p less than .005); it increased cardiac index 8.8% (p less than .025) and global ejection fraction 9.1% (p less than .0001). However, left ventricular end-diastolic pressure increased 14.2% (p less than .001) and the left ventricular end-systolic pressure-volume (P-V) ratio decreased 8.8% (p less than .02). Diltiazem decreased the time constant of left ventricular relaxation by 14.3% (p less than .002), despite lack of change in the left ventricular diastolic P-V relationship, in 16 patients. Diltiazem caused a significant increase in area ejection fraction in 53% of hypokinetic areas supplied by diseased arteries compared with 13% of normokinetic areas supplied by diseased arteries (p less than .0001). Response of ejection fraction to diltiazem in areas supplied by normal coronary arteries was less (p less than .05) than that in hypokinetic areas supplied by arteries affected by disease. In conclusion, diltiazem improves regional wall motion abnormalities in patients with CAD and the improvement is associated with better left ventricular relaxation but not with a change in the diastolic P-V relationship. Global indexes of left ventricular systolic performance are favorably influenced by diltiazem, despite a mild negative inotropic effect.

Paradoxical deterioration of left ventricular asynergy after administration of nitroglycerin

The effects of nitroglycerin on segmental asynergy were studied by 2-dimensional echocardiography. Forty-five patients with coronary artery disease and segmental wall motion abnormality at rest were examined, 31 with Q-wave and 14 with only ST-T abnormalities. Left ventricular (LV) echocardiograms were recorded from the LV apex in 4 planes, obtained by systematically rotating the transducer at 45 degrees intervals around the mitral office, using a mechanical device. Sixteen LV segments were analyzed in each patient on real-time display by 2 observers independently. The wall motion analysis was classified as normal, hypokinetic, akinetic or dyskinetic. Of 720 segments, 596 were agreed on by 2 observers in the assessment of wall motion before and after administration of nitroglycerin: 334 segments (56%) showed no change in wall motion, 206 (35%) showed improvement of wall motion and 56 (9%) showed worsening of myocardial asynergy after nitroglycerin. These data suggest that administration of nitroglycerin may result in unexpected worsening of segmental asynergy. This may be secondary to an adverse effect of a decrease in perfusion pressure in critically occluded arteries or may represent a coronary steal phenomenon.

Ischemic cardiomyopathy

The term "ischemic cardiomyopathy" was used initially to describe a clinical syndrome that was indistinguishable from primary congestive cardiomyopathy but due to severe, diffuse coronary artery disease. The term has been expanded to include the larger category of myocardial disease secondary to coronary artery disease. Using this expanded definition, we have discussed the varied clinical presentations of congestive ischemic cardiomyopathy and restrictive ischemic cardiomyopathy (stiff heart syndrome and right ventricular infarction), and how the effects of ischemia on left ventricular systolic and diastolic performance may cause these varied presentations. The prognosis of any ischemic cardiomyopathy is related primarily to the degree of ventricular dysfunction and the extent of coronary artery disease. Therapy is aimed at preventing or ameliorating myocardial ischemia and halting the progression of, or even reversing, the deterioration in myocardial function.

Three-dimensional analysis of regional myocardial function in response to nitroglycerin in patients with coronary artery disease

Biplane cineventriculography was performed at rest and after sublingual nitroglycerin in 13 patients with coronary artery disease. In six patients (responders), there was a significant increase in ejection fraction [40 +/- 5 to 52 +/- 4% (p less than 0.001)], while in the other seven (nonresponders), there was no alteration in ejection fraction. To evaluate the extent of regional myocardial response to nitroglycerin, the contractile pattern of the regional myocardium over the entire ventricular surface was analyzed using a computer-generated three-dimensional model. The spatial coordinates that define the elliptic ventricular surface on a given horizontal plane cross section of the chamber were determined by four counter values in the two orthogonal silhouettes. Then, 32 points at equal angles around the center of gravity of the end-diastolic cavity were generated to form the border image. Repetition of this process for 16 successive cross sections allowed for reconstruction of the ventricular surface by the sequence of 32 X 16 (512) points. The regional wall motion was expressed as the percent change of the radial length, drawn from the center of gravity to each surface point. There was significant heterogeneity in regional response to nitroglycerin. In the responders, the normally contracting area was significantly increased (from 16.5 +/- 16.0 to 36.2 +/- 14.9% of the total surface area, p less than 0.001), largely mediated by the greater improvement in segmental shortening of each graded contractile pattern relative to its deterioration. In the nonresponders, a lessening of the severe dysfunction of the given area was associated with significant deterioration of segmental shortening of the other normally contracting area (49.1 +/- 19.7% of the area with a contractile pattern of grade 5 had deteriorated, p less than 0.05). Thus, the ratio of the area with respective graded segmental shortening was virtually unchanged. These differences in response of the ischemic ventricle to nitroglycerin appeared to be related to the development of adequate coronary collateral vessels as well as to an interaction of changes in preload and afterload.

Quantitative variability in regional wall motion during serial left ventricular cineangiography: guidelines for assessing changes in segmental function with intervention studies

To assess the random variation in left ventricular (LV) volume and regional wall motion that occurs with quantitative analysis of LV cineangiography, 15 patients underwent 2 serial biplane LV cineangiograms in the 30 degrees right anterior oblique and 60 degrees left anterior oblique projections. Cineangiograms were separated by a waiting period of at least 15 minutes. Regional wall motion was quantitated with an area ejection fraction (EF) technique that divides the left ventricle into 8 areas. There were no significant changes in heart rate, mean arterial pressure or LV pressure or volume between the first and second angiograms. However, global EF increased from 0.57 +/- 0.11 to 0.58 +/- 0.10 (p = 0.055). Random variability in area EF was greatest in the septal and low posterolateral regions and least in the inferior and inferobasal regions of the left ventricle. Using linear regression analysis to obtain 95% confidence intervals, we determined the amount of absolute increase in area EF that must occur to be considered significant for each LV region. This amount varies from area to area and is as little as +/- 0.06 in the inferior region (area 4) and as high as +/- 0.16 in the septum (area 8). These data provide guidelines for the determination of the influence of interventions on regional wall motion in individual patients with cardiac disease, and indicate that statistically significant changes in regional wall motion are clinically important.

Haemodynamics and plasma concentrations following sublingual GTN and intravenous, or inhaled, isosorbide dinitrate

We measured plasma nitrate levels and haemodynamics following sublingual glyceryl trinitrate (GTN) (0.5 mg), or isosorbide dinitrate (ISDN) administered intravenously (0.5 mg) or by inhalation (1.25 mg) in 23 patients undergoing cardiac catheterisation for investigation of chest pain. Peak levels were detected at 90 s and 5 min following intravenous and inhaled ISDN respectively and at 3 min following sublingual GTN. Intravenous and inhaled ISDN produced similar plasma levels at 30 s and both were significantly greater than following sublingual GTN. Plasma levels were maintained for longer following inhaled ISDN than intravenous ISDN or sublingual GTN. Haemodynamic responses were qualitatively similar following each treatment; reduction in pulmonary vascular resistance and pressure and left ventricular end diastolic pressure occurred in each group. Heart rate, cardiac output and LV dP/dt.P-1 remained unchanged. Maximal haemodynamic responses were greater following ISDN than GTN, with little difference between the two preparations of ISDN. Haemodynamic responses were more sustained following inhaled ISDN than following sublingual GTN or intravenous ISDN, the latter two being similar in this respect. These findings suggest that inhaled ISDN may provide more rapid and sustained relief from angina than sublingual GTN.

Morphology of ventricular premature beats as an aid in the electrocardiographic diagnosis of myocardial infarction

To determine whether morphologic analysis of ventricular premature beats (VPBs) can aid in the electrocardiographic diagnosis of myocardial infarction (MI), 12-lead electrocardiograms were evaluated in 760 consecutive patients who underwent cardiac catheterization, and 2-minute multiple-lead rhythm strips were evaluated in 515 of these patients. VPBs occurred in 58 patients; 21 had prior MI diagnosed by regional akinesia or dyskinesia on left ventricular cineangiography. Standard criteria were used to diagnose prior MI from the sinus beats of the electrocardiogram. Infarction was diagnosed from the morphology of a VPB when it had a QR or QRS pattern with Q wave greater than or equal to 0.04 second. Morphologic analysis of VPBs had a low sensitivity (29%) but high specificity (97%) and high predictive value (86%) for the diagnosis of MI. Sinus beats diagnosed MI with higher sensitivity (52%, and 69% if patients with left bundle branch block and left ventricular hypertrophy were excluded from analysis) than VPB morphologic analysis (p less than 0.05), but with similar specificity (97%) and predictive value (92%). Two patients with angiographic MI had no MI according to standard electrocardiographic criteria, but did have an MI manifest by VPB morphologic analysis. Despite low sensitivity, analysis of the morphology of VPBs may be useful for the diagnosis of MI when the morphology of sinus beats is not diagnostic. Therefore, VPB analysis is complementary to the standard electrocardiographic diagnosis of MI.

Acute changes in infranodal conduction time following left ventriculography and sublingual nitroglycerin administration in man

During diagnostic cardiac catheterization for the evaluation of chest pain, His bundle electrograms were obtained in 32 male patients before and 2 to 5 minutes after each of two interventions known to acutely affect left ventricular volume and left ventricular end-diastolic pressure (the injection of 40 to 60 cc of contrast medium during left ventriculography and the administration of 0.4 mg of sublingual nitroglycerin). Changes in left ventricular end-diastolic pressure (18 +/- 6 vs 30 +/- 7 mm Hg, p less than 0.001 following ventriculography and 32 +/- 8 vs 19 +/- 8 mm Hg, p less than 0.005 following nitroglycerin administration) were accompanied by parallel alterations in HQ (48 +/- 8 vs 54 +/- 10 msec, p less than 0.005 following ventriculography and 57 +/- 10 vs 53 +/- msec, p less than 0.005 following nitroglycerin administration), but there were no significant changes in atrioventricular (AV) nodal conduction (AH). Significantly greater changes in HQ were seen in patients with triple-vessel coronary artery disease than in the remainder of the population, although there was clinical and/or ECG evidence of ischemia in only one patient. We conclude that factors other than progression of intrinsic conduction system disease may affect infranodal conduction. HQ should be interpreted cautiously in situations with rapidly changing hemodynamics, especially in patients with severe coronary artery disease.

Implications of normal exercise electrocardiographic results in patients with angiographically documented coronary artery disease. Correlation with left ventricular function and myocardial perfusion

The purpose of this study was to examine the incidence and implications of false-negative exercise electrocardiographic results among 216 consecutive patients with angiographically documented coronary artery disease (50 percent diameter narrowing or greater of one or more vessels). Exercise electrocardiography gave negative (false-negative) results in 23 patients and positive (true-positive) results in 102 patients, and were nondiagnostic in the rest. Exercise thallium-201 imaging was performed in 88 patients. The extent of coronary artery disease was quantitated by a scoring system that takes into consideration the degree and site of narrowing in the major vessels and their branches. The exercise heart rate was higher in patients with false-negative than in patients with true-positive exercise electrocardiographic results (161 +/- 18 versus 133 +/- 24 beats per minute, mean +/- SD; p less than 0.0001). Q-wave infarction was present in two patients (9 percent) with false-negative and 20 patients (20 percent) with true-positive exercise electrocardiographic results (p = NS); left ventricular asynergy at rest was observed in 13 patients (57 percent) with false-negative and in 74 patients (74 percent) with true-positive results (p = NS). Patients with false-negative results had less extensive coronary disease than did patients with true-positive results (score 5.8 +/- 3.6 versus 9.2 +/- 5.0; p = 0.0025). Angina during exercise was less frequent in patients with false-negative results (p less than 0.01). Abnormal exercise thallium-201 images were seen in 15 of 20 patients (75 percent) with false-negative results and in 56 of 68 patients (82 percent) with true-positive results (p = NS). It is concluded that (1) false-negative exercise electrocardiographic results are infrequent (10 percent) among patients with coronary artery disease and are associated with less extensive coronary artery disease; (2) the frequency of Q-wave infarction and left ventricular asynergy is the same in patients with false-negative results as in patients with true-positive exercise electrocardiographic results; (3) exercise thallium images can identify 75 percent of patients with coronary disease and false-negative results of exercise electrocardiography.

Vasodilator therapy in chronic congestive heart failure

Vasodilator agents are relatively new additions to the armamentarium for the management of patients with congestive heart failure. Myocardial failure, irrespective of the aetiology, tends to create a vicious cycle characterised by reduced cardiac output and elevated systemic vascular resistance, which further decrease cardiac output by increasing left ventricular ejection impedance. The rationale for the use of vasodilators is to interrupt the vicious cycle by decreasing the left ventricular ejection impedance by peripheral vasodilatation. Although most vasodilator agents produce qualitatively similar haemodynamic responses, quantitatively their haemodynamic effects differ considerably. Knowledge of the haemodynamic effects of the various vasodilators helps in the selection of a particular drug for the management of such patients. This article reviews the mechanisms of action, haemodynamic effects, pharmacokinetics, clinical usage and adverse effects of non-parenteral vasodilator agents currently available for the management of patients with chronic heart failure.

Relation between functional response to nitroglycerin and extent of myocardial necrosis in dogs: mapping of the left ventricle by 2-dimensional echocardiography

The relation between functional response to brief nitroglycerin infusions and extent of myocardial damage was studied sequentially in closed-chest dogs with acute occlusion of the left anterior descending coronary artery. Two-dimensional echocardiography was used to derive segmental left ventricular (LV) function (systolic fractional area change and systolic wall thickening), and this function was compared with the extent of necrosis measured 5 hours after occlusion in equivalent segments of corresponding pathologic slabs. Two-dimensional echocardiographic study before the dogs were killed indicated that remote nonnecrotic segments always responded to nitroglycerin by significant augmentation of segmental LV function. Segments in which necrosis was less than 40% showed a significant nitroglycerin-induced potentiation in segmental LV function. In contrast, segments in which necrosis was greater than 60% had no potentiation with nitroglycerin. In those segments in which eventual necrosis was 60 to 80%, significant nitroglycerin-induced augmentation in segmental LV function was observed only before and 30 minutes after the coronary occlusion. When the degree of necrosis was greater than 80%, no significant potentiation of segmental LV function was observed even as early as 30 minutes after occlusion. Thus, the degree of nitroglycerin-induced potentiation of segmental cardiac function is closely associated with the extent of myocardial necrosis in the particular ventricular segment. Two-dimensional echocardiography coupled with a nitroglycerin potentiation test might be useful for assessment of the viability of ischemic myocardium.

Hemodynamic, angiographic and scintigraphic correlates of positive exercise electrocardiograms: emphasis on strongly positive exercise electrocardiograms

The results of treadmill exercise electrocardiograms were analyzed in 179 patients with coronary artery disease (greater than or equal to 50% diameter narrowing of one or more vessels). Exercise thallium-201 images were available in 141 of these patients. The exercise electrocardiograms were strongly positive in 51 patients, mildly positive (1 to 1.9 mm ST depression) in 28 patients, falsely negative in 23 patients and uninterpretable in 77 patients. The degree of exercise-induced ST depression did not correlate with left ventricular function, extent of coronary artery disease, exercise heart rates and rate-pressure product and extent of exercise-induced thallium-201 perfusion abnormality. However, the presence of a strongly positive exercise electrocardiogram only at heart rates of 140 beats/min or more or stage III or higher of the Bruce protocol was predictive of less extensive coronary disease and perfusion abnormalities. Thus, the magnitude of ST depression as such during exercise is not predictive of the extent of coronary disease, even in patients with 3 mm or greater ST depression. However, a strongly positive exercise electrocardiogram in the first two stages of the Bruce protocol or at a heart rate of less than 140 beats/min was related to the extent of coronary artery disease and impaired myocardial perfusion, and identified patients with more extensive coronary artery disease and jeopardized myocardium. Therefore, caution should be used in interpreting prognostic data on the basis of the degree of exercise-induced ST depression alone.

The effect of nitroglycerin cardioplegia on myocardial cooling in patients undergoing myocardial revascularization

The effect of intracoronary administration of nitroglycerin on the distribution of cardioplegia and myocardial cooling was assessed in 45 patients undergoing elective myocardial revascularization. The patients were divided into three groups. Myocardial temperature was measured over the right and left coronary artery distributions in Group 1 after the infusion of 1 liter of potassium blood cardioplegic solution (20 mEq of potassium per liter). Similar temperature measurements were made in Group 2 after the addition of 300 micrograms of nitroglycerin to the cardioplegic solution and in Group 3 after the addition of 1,000 micrograms of nitroglycerin. Nitroglycerin did not affect myocardial cooling, and large temperature gradients persisted after delivery of cardioplegia in patients with occlusive coronary artery disease. Unexpectedly, however, the rate of cardioplegia delivery increased by 134%, within the same range of infusion pressures, in patients receiving nitroglycerin. Although nitroglycerin cardioplegia does not affect the regional disparity in the distribution of cardioplegia in patients with severe coronary artery disease, intracoronary administration of nitroglycerin reduces the time required for administration of cardioplegia and thereby decreases the total ischemia time.

A profile of intravenous nitroglycerin use in cardiopulmonary bypass surgery

We studied the indications for use, time to onset of effect, approximate effective concentration and therapeutic success of commercially prepared intravenous nitroglycerin (NTG) in 50 patients undergoing cardiopulmonary bypass (CPB) surgery. Nitroglycerin was used to treat systemic or pulmonary hypertension, myocardial ischaemia and ventricular failure. Twenty-one patients had more than one indication for NTG use. Nineteen of 22 patients with pulmonary hypertension, 12 of 13 patients with ischaemic changes, and 13 of 15 patients with ventricular failure improved during intravenous NTG administration. Hypertension during CPB was ameliorated in only six of ten instances. The time to onset of effect ranged from 4.1 +/- 0.8 to 7.8 +/- 2.8 minutes and the mean approximate effective NTG concentration varied from 1.7 +/- 0.3 to 2.9 +/- 0.7 micrograms . kg-1.min-1 (doses only approximate due to our use of an infusion system which absorbs NTG). Complications from intravenous NTG administration were not seen. We conclude that this NTG preparation facilitates treatment of prebypass hypertension, pulmonary hypertension, myocardial ischaemia and ventricular failure but is less effective for the treatment of hypertension during CPB.

Vasodilator therapy for acute myocardial infarction and chronic congestive heart failure

Vasodilator therapy is useful adjunctive therapy in the management of both acute and chronic heart failure. Arteriolar dilators, such as hydralazine, increase cardiac output by decreasing the elevated peripheral vascular resistance that occurs in heart failure. Venodilators, such as nitrates, decrease ventricular filling pressures by redistributing blood so that more is pooled in peripheral veins. Vasodilators that produce both effects (nitro-prusside, prazosin, captopril, for example) are usually helpful in short-term improvement of hemodynamics. Long-term treatment with nonparenteral vasodilators often reduces symptoms and increases exercise tolerance, although there is inconclusive evidence regarding the effects of these agents on mortality. In acute myocardial infarction, intravenous vasodilators frequently improve cardiac performance. Evidence regarding their beneficial effects on infarct size and immediate mortality is encouraging but inconclusive. There is little evidence that they prolong life in patients who survive cardiogenic shock and leave the hospital. Thus, vasodilators can improve hemodynamics and lessen symptoms, but more evidence is needed regarding their long-term effects on survival.

The significance of nitroglycerin-induced changes in ventricular function after acute myocardial infarction

The potential of nitroglycerin for improving global and regional ventricular function after acute myocardial infarction and predicting serial change in ventricular function at the time of hospital discharge was investigated. Equilibrium multiple gated blood pool scintigrams were performed at rest before and after sublingual administration of nitroglycerin in 18 patients an average of 36 hours after infarction and again at discharge. Global right and left ventricular function and regional left ventricular function of infarct and noninfarct zones were determined scintigraphically. In the early study nitroglycerin increased both mean (+/- standard deviation) left ventricular ejection fraction (0.51 +/- 0.15 to 0.55 +/- 0.15 ; p less than 0.02) and mean right ventricular ejection fraction (0.42 +/- 0.14 to 0.47 +/- 0.13; p less than 0.05). Left ventricular ejection fraction significantly increased in 5 of the 18 patients. It increased late in five of the six patient who exhibited an increase early after nitroglycerin but in only 2 of the 12 patients who did not exhibit an early increase (p less than 0.06). Regional ejection fraction in the infarct zone increased late in 7 of the 12 patients who exhibited an early increase after nitroglycerin and in none of the 6 who did not exhibit an early increase (p less than 0.05). Both right and left ventricular global ejection fraction and regional ejection fraction showed little late responsiveness to nitroglycerin. Early after infarction, sublingual nitroglycerin improved left, right and regional ejection fraction at the infarct site in some patients. These nitroglycerin-induced changes predicted those patients whose global ventricular function and regional left ventricular function at the infarct site improved late.

Advantages of the caudocranial left anterior oblique left ventriculogram in adult heart disease

Biplane axial left cineventriculography represents the most accurate diagnostic technique for evaluating acquired and congenital heart disease. However, data have accumulated to indicate that without angled views of the left ventricle, the diagnosis will be incomplete and inaccurate in a significant number of patients. Left ventriculography is the acknowledged standard for left ventricular performance. However, comparison of the conventional or nonangled left anterior oblique left ventriculogram with the angled views of the left ventricle obtained with either two dimensional ultrasound or radionuclide left ventriculography may in many cases be invalid because dissimilar views are compared. The cranial-left anterior oblique view allows more accurate assessment of the precise degree and extent of asynergy, left ventricular aneurysms and ventricular septal defects. Left ventricular outflow tract abnormalities such as discrete subaortic stenosis and the obstructive form of hypertrophic cardiomyopathy can easily be distinguished. Lesions involving the mitral valve, especially mitral valve prolapse, are readily evaluated. Lastly, comparison with noninvasive tests of left ventricular performance can be more accurately performed.

Left ventricular wall motion improvement after phentolamine: a case report

Left ventricular wall motion abnormalities are commonly seen in coronary artery disease patients. The differentiation between reversibly ischemic areas an irreversibly damaged areas is 1 was of predicting which patient might gain improved ventricular function from surgical correction. One patient with coronary artery disease is presented here who showed poor septal movement on his echocardiogram. After the IV administration of phentolamine, the septal movement became normal. Thus, phentolamine should be considered as an agent that can detect reversible areas of wall motion abnormalities.

Validation of geometric methods for estimating segmental myocardial motion of the left ventricle at cineangiography

Functional myocardial changes which result from ischemia are typically local rather than total. For assessing such regional changes quantitatively, left ventricular angiography has been used. The ventricular image has been divided into several components which can be measured individually. In order to test the validity of such methods, left ventricles of 5 dogs were labeled with endocardial tantalum markers and the segmental myocardial motion was estimated using cineangiography. Variance analysis of beat to beat measurements of total ejection fractions was performed. Total ejection fraction demonstrated the least variation with an average 3.5 per cent, segmental myocardial shortening 15 and regional stroke volumes 13 to 18 per cent. Intermethodologic variation with different regional volume measurements was 11 to 13 per cent. Regional stroke volume calculations showed large methodologic variations in beat to beat analysis. Conclusions and clinical decisions based on such measurements should be drawn with caution.

Combined vasodilator and inotropic therapy of heart failure: experimental and clinical concepts

Vasodilators facilitate ventricular emptying by affording earlier onset of left ventricular (LV) ejection and increased stroke volume with achievement of a reduced end-systolic pressure and volume. Agents with positive inotropic properties increase stroke volume by shifting the end-systolic pressure-volume curve to the left through augmented force and velocity of contraction. With impedence reduction, improvement in pump performance occurs concomitant with reduced cardiac energy requirements (MVO2); positive inotropic agents most circumstances increase MVO2. The combination of a vasodilator and positive inotropic agent, as opposed to either alone, in the conscious animal shifts to the left and increases the slope of the LV end-systolic pressure-volume relation. Cardiac efficiency, defined by the slope of the relation between stroke volume and systolic tension, is increased by the combination of the drugs. In clinical heart failure, nitroprusside alone lowers LV preload with a modest increase in cardiac output (CO); dopamine markedly increases CO with little fall in LV preload. In combination the two agents achieve the individual beneficial effects of each drug, and cardiac efficiency indices are improved. Thus combined vasodilator and inotropic therapy appears to have a sound physiologic rationale and clinically documented beneficial effect superior to either modality alone.

Comparative evaluation of segmental asynergy in remote myocardial infarction by radionuclide angiography, two-dimensional echocardiography, and contrast ventriculography

Radionuclide angiography (RNA), two-dimensional echocardiography (2DE), and contrast ventriculography (CVG) were compared in the evaluation of regional wall motion (RWM) in 58 patients with remote myocardial infarction (MI). All 58 patients were studied by 2DE, 52 by RNA, and 24 by CVG. Severe degrees of segmental asynergy (akinesia/dyskinesia) were noted more often by 2DE (56% of all segments, p less than 0.005) and CVG (52%, p less than 0.05) than by RNA (39%). The apex more the most frequent site of akinesia/dyskinesia by all technique (43% by RNA, 36% by 2DE, and 45% by CVG). 2DE and RNA agreed in 64% of regions (p less than 0.005), 2DE and CVG agreed in 68% (p less than 0.005), and RNA and CVG agreed in 70% (p less than 0.005); the highest agreement was for the apical region. Dyskinesia was noted in 77% of patients by RNA, in 71% by 2DE, and 79% by CVG. RNA and CVG agreed in 89% of patients and in 57% of regions, 2DE and CVG agreed in 67% of patients and in 53% of regions, and RNA and 2DE agreed in 71% of patients and in 38% of regions. Combined RNA and 2DE detected dyskinesia in 94% of the 16 patients with dyskinesia by CVG who underwent all three techniques and in 90% of the 52 patients studied by RNA and 2DE. We conclude that (1) RNA, 2DE an CVG agree significantly in the evaluation of regional wall motion; (2) there is better agreement concerning the presence or absence of dyskinesia in a given patients than the exact region involved; and (3) the combination of RNA and 2DE is more useful than either alone as a screening procedure for the detection of ventricular dyskinesia.

Pharmacologic intervention in cardiovascular nuclear medicine procedures

Relevant questions in ischemic heart disease are (1) what is the ischemic threat? (2) What is the extent of ventricular dysfunction? (3) Is the observed dysfunction reversible? Exercise testing can help to identify the ischemic threat. Catheterization studies have shown that resting ventricular dysfunction can be reversed in some patients through pharmacologic or surgical intervention. However, improved ventricular performance in ischemic heart disease may be achieved through a variety of mechanisms. Insight into all components of cardiac performance (regional and global contractillity, preload, afterload, and heart rate) and myocardial perfusion may be required to adequately describe the influence of intervention. Exercise radionuclide ventriculographic studies have demonstrated that stress-induced ventricular dysfunction can be reversed through surgical and pharmacologic intervention. Studies at rest have demonstrated that radionuclide techniques can detect drug-induced changes in ventricular performance in groups of patients. The challenge to cardiovascular nuclear medicine is the prospective identification of patients who would benefit most from aggressive intervention aimed at preventing or reversing ischemic ventricular dysfunction.

Semiautomated method for evaluation of left ventricular regional wall motion in coronary artery disease

Regional left ventricular wall motion was independently assessed in 436 patients using both subjective visual inspection of ventriculograms and objective computer-determined percent change in the square root of the area between systolic and diastolic outlines. Agreement between subjective and objective techniques was greatest at the ventricular apex and least at the base and partly dependent on the number of abnormal segments present. Objective analysis of regional wall motion provides a permanent quantitative record of wall motion and shows good agreement with meticulous subjective inspection of ventriculograms. As such, it has potential as an adjunct to ventriculography.

Limitations of two frame method for displaying regional left ventricular wall motion in man

Regional abnormalities of left ventricular function are frequently determined from superimposed cavity outlines at end-diastole and end-systole. The timing of end-diastole is standardised with respect to the electrocardiogram, but that of end-systole is undefined, and frequently determined by simple inspection. To examine the effect of variation in the timing of the end-systolic frame on apparent regional wall motion, 35 left ventricular angiograms from patients wit ischaemic heart disease were digitised frame by frame, and the timing of aortic valve closure and mitral valve opening superimposed on contour displays. In 15 patients, the pattern in the two frame display with end-systole taken as aortic valve closure was similar to that when it was taken as mitral valve opening. In the remaining 20, however, there were major discrepancies between the two, because of changes in cavity shape during isovolumic relaxation. These shape changes were the result of asynchronous termination of systole in different regions of the ventricle. In addition, there was a significant increase in left ventricular cavity area of 3.9 +/- 1.7 per cent during isovolumic relaxation, corresponding to an increase in calculated volume of 8.1 +/- 4.5 per cent. Estimates of ejection fraction derived from end-systole taken at end-ejection were thus consistently greater than those at mitral valve opening. These differences in the apparent pattern of regional wall motion resulting from lack of definition of end-systole are large compared with those reported after intervention angiography, or surgery. Thus, if two frame methods are to be used, the timing of end-systole must be standardised. We suggest that end-ejection be used. Changes of shape during isovolumic relaxation should be considered separately.